In a universal mobile telecommunication system (UMTS), a feature of enhanced uplink transmission in an idle or a cell forward access channel (Cell_FACH) state is introduced for a user equipment (UE) in the idle state or the Cell_FACH state, and an enhanced dedicated channel (E-DCH) is used to replace a random access channel (RACH). The UE in the idle state or the Cell_FACH state may send uplink data to a base station (NodeB) by using acquired uplink common E-DCH resources at a pre-configured transmission time interval (TTI).
At an Iub interface between the NodeB and a radio network controller (RNC), the NodeB sends the uplink data of the UE to the RNC through an E-DCH data frame. The E-DCH data frame is used to bear a media access control (MAC) protocol data unit (MAC PDU) of the UE in the Cell-FACH state or the idle state. For the UE in the Cell-FACH state or the idle state, when the TTI length is configured to be 2 milliseconds (ms), the RNC may configure, by configuring a bundling mode indicator information element of a common media access control flow (common MAC flow), a sending mode of the E-DCH data frame of the common MAC flow at the Iub interface.
If a physical shared channel reconfiguration request includes the bundling mode indicator, and the UE uses the 2 ms TTI, the NodeB sends the relevant uplink common MAC flow according to the bundling mode indicator.
In the prior art, for the enhanced uplink transmission feature, each cell can be configured with only one uplink TTI, and the UE, when transmitting the uplink data, can use only the 2 ms TTI or a 10 ms TTI, and therefore, the RNC may acquire the TTI used by the UE in each cell.
However, in a subsequent evolved version, it is possible that each cell is configured with two TTIs, that is, in the same cell, a UE supporting enhanced uplink transmission may dynamically select the 2 ms TTI or the 10 ms TTI for transmitting uplink data. The TTI selection may be performed according to a location where the UE is located. For example, when the UE is located at the edge of a cell and power is limited, the UE may use the 10 ms TTI to enhance coverage of the uplink; when the UE is located at the middle of the cell and the power is sufficient, the UE may use the 2 ms TTI to increase a transmission rate of the uplink. In this scenario, the RNC cannot acquire the TTI used by the UE in the Cell-FACH state or the idle state when transmitting the uplink data, and as a result, when the UE transits from the Cell-FACH state to the cell dedicated transmission channel (Cell-DCH) state, the RNC cannot select and configure an appropriate TTI for the UE.